/*
 * Added the following header as some of the source in this class
 * has been derived from material (and example classes) in the Java
 * Tutorial.
 * 
 * Copyright 2001-2002 Sun Microsystems, Inc. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or 
 * without modification, are permitted provided that the following 
 * conditions are met:
 * 
 * -Redistributions of source code must retain the above copyright  
 * notice, this  list of conditions and the following disclaimer.
 * 
 * -Redistribution in binary form must reproduct the above copyright 
 * notice, this list of conditions and the following disclaimer in 
 * the documentation and/or other materials provided with the 
 * distribution.
 * 
 * Neither the name of Sun Microsystems, Inc. or the names of 
 * contributors may be used to endorse or promote products derived 
 * from this software without specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any 
 * kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND 
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 */

package org.ds.auth;

import javax.security.auth.callback.Callback;
import javax.security.auth.callback.CallbackHandler;
import javax.security.auth.callback.NameCallback;
import javax.security.auth.callback.PasswordCallback;
import javax.security.auth.callback.UnsupportedCallbackException;

import org.ds.util.ApplicationContext;

/**
 * A custom implementation of the CallbackHandler interface. As of now
 * just handles Username and Password callbacks. Gets the username and
 * password that need to be authenticated from an ApplicationContext
 * class.
 *  
 * @author Kartick Suriamoorthy
 */
public class DSCallbackHandler implements CallbackHandler
{

	/**
	 * As of now contains a very simple implementation. Gets the username
	 * and password from an ApplicationContext class and sets it on the
	 * NameCallback and PasswordCallback instances respectively. If the
	 * Callback instance is neither a NameCallback nor a PasswordCallback,
	 * the an UnsupportedCallbackException is thrown.
	 */
	public void handle(Callback[] callbacks) throws UnsupportedCallbackException
	{
		for (int i = 0; i < callbacks.length; i++)
		{
			if (callbacks[i] instanceof NameCallback)
			{
				// get the username that will be used for authentication
				NameCallback nc = (NameCallback) callbacks[i];

				ApplicationContext appContext = ApplicationContext.getInstance();
				String username = appContext.getLoginUser().getUsername();

				// set the username on the NameCallback instance
				nc.setName(username);
			}
			else if (callbacks[i] instanceof PasswordCallback)
			{
				// get the password that will be used for authentication
				PasswordCallback pc = (PasswordCallback) callbacks[i];

				ApplicationContext appContext = ApplicationContext.getInstance();
				String password = appContext.getLoginUser().getPassword();

				// set the password on the PasswordCallback instance
				pc.setPassword(password.toCharArray());
			}
			else
			{
				throw new UnsupportedCallbackException(callbacks[i], "Unrecognized Callback");
			}
		}
	}
}
